Class Context

Nested Relationships

Nested Types

Class Documentation

class Context

Specifies SeQuant context, such as vacuum choice, whether index spaces are orthonormal, sizes of index spaces, etc.

SeQuant context contains the following information:

  • a IndexSpaceRegistry object: contains information about the known IndexSpace objects and their attributes; managed by shared_ptr and can be shared by multiple contexts.

  • vacuum: the vacuum state used to define normal ordering of NormalOperators

  • metric: whether the plain basis of vector space (ket) modes are orthonormal to their dual (bra) counterparts (IndexSpaceMetric::Unit) or not (IndexSpaceMetric::General); this affects the value of Wick contractions.

  • braket_symmetry: whether the primal (ket) and dual (bra) vector space bases are “equivalent” (homogenous to each other; BraKetSymmetry::Symm), “conjugate to each other” (conjugate-homogenous to each other; BraKetSymmetry::Conjugate) or are “nonequivalent” (not homogeneous; BraKetSymmetry::Nonsymm)

  • spbasis: whether the bra/ket bases are spinor (SPBasis::Spinor) or spin-free (SPBasis::Spinfree).

  • first_dummy_index_ordinal: during its operation SeQuant will generate temporary indices with orbitals greater or equal to this; to avoid duplicates user Index objects should have ordinals smaller than this

  • canonicalization_options: if set, this specifies the default options to use for canonicalization of expressions.

  • braket_typesetting: whether to_latex() typesets tensor indices of ket (covariant, primal) modes as superscript (BraKetTypesetting::KetSuper, default)

  • braket_slot_typesetting: whether to_latex() typesets tensor indices using tensor LaTeX package (BraKetSlotTypesetting::TensorPackage, default) or native typesetting (BraKetSlotTypesetting::Naive); the former is preferred for alignment of superscript with subscript slots.

Public Functions

Context(Options options = make_default_options())

standard named-parameter constructor

Warning

default constructor does not create an IndexSpaceRegistry, thus this->index_space_registry() will return nullptr Example: 

Context ctx({.vacuum = Vacuum::SingleReference, .spbasis = SPBasis::Spinfree});

~Context() = default
Context(const Context &ctx) = default

copy constructor

See also

clone()

Warning

created Context uses the same index space registry as ctx

Parameters:

ctx – [in] a Context

Context &operator=(const Context &ctx) = default

copy assignment

See also

clone()

Warning

this object will use the same index space registry as ctx

Parameters:

ctx – [in] a Context

Returns:

reference to this object

Context clone() const

clones this object AND its index space registry

Note

created Context does not use this object’s index space registry

Context(Context&&) = default
Vacuum vacuum() const
Returns:

Vacuum of this context

std::shared_ptr<const IndexSpaceRegistry> index_space_registry() const

Warning

can be null when user did not provide one to Context (i.e., it was default constructed)

Returns:

a constant pointer to the IndexSpaceRegistry for this context

std::shared_ptr<IndexSpaceRegistry> mutable_index_space_registry() const
Throws:

std::logic_error – if the IndexSpaceRegistry is null

Returns:

a pointer to the IndexSpaceRegistry for this context.

IndexSpaceMetric metric() const
Returns:

IndexSpaceMetric of this context

BraKetSymmetry braket_symmetry() const
Returns:

BraKetSymmetry of this context

SPBasis spbasis() const
Returns:

SPBasis of this context

std::size_t first_dummy_index_ordinal() const
Returns:

first ordinal of the dummy indices generated by calls to Index::next_tmp_index when this context is active

std::optional<CanonicalizeOptions> canonicalization_options() const
Returns:

canonicalization options to use by default, if nonnull

BraKetTypesetting braket_typesetting() const
Returns:

BraKetTypesetting of this context; if this returns BraKetTypesetting::ContraSub covariant (ket, creation) and contravariant (bra, annihilation) indices are typeset in superscript and subscript LaTeX, respectively.

BraKetSlotTypesetting braket_slot_typesetting() const
Returns:

BraKetSlotTypesetting of this context; see BraKetSlotTypesetting for the meaning of the possible values

Context &set(Vacuum vacuum)

Sets the Vacuum for this context, convenient for chaining

Parameters:

vacuum – Vacuum

Returns:

ref to *this, for chaining

Context &set(IndexSpaceRegistry ISR)

sets the IndexSpaceRegistry for this context

Parameters:

ISR – an IndexSpaceRegistry

Returns:

ref to ‘*this’ for chaining

Context &set(std::shared_ptr<IndexSpaceRegistry> ISR)

sets the IndexSpaceRegistry for this context

Parameters:

ISR – a IndexSpaceRegistry shared_ptr

Returns:

ref to ‘*this’ for chaining

Context &set(IndexSpaceMetric metric)

Sets the IndexSpaceMetric for this context, convenient for chaining

Parameters:

metric – IndexSpaceMetric

Returns:

ref to *this, for chaining

Context &set(BraKetSymmetry braket_symmetry)

Sets the BraKetSymmetry for this context, convenient for chaining

Parameters:

braket_symmetry – BraKetSymmetry

Returns:

ref to *this, for chaining

Context &set(SPBasis spbasis)

Sets the SPBasis for this context, convenient for chaining

Parameters:

spbasis – SPBasis

Returns:

ref to *this, for chaining

Context &set_first_dummy_index_ordinal(std::size_t first_dummy_index_ordinal)

Sets the first dummy index ordinal for this context, convenient for chaining

Parameters:

first_dummy_index_ordinal – the first dummy index ordinal

Returns:

ref to *this, for chaining

Context &set(CanonicalizeOptions copt)

Specifies the canonicalization options

Returns:

ref to *this, for chaining

Context &set(BraKetTypesetting braket_typeset)

Sets the BraKetTypesetting for this context, convenient for chaining

Parameters:

braket_typeset – BraKetTypesetting

Returns:

ref to *this, for chaining

Context &set(BraKetSlotTypesetting braket_slot_typeset)

Sets the BraKetSlotTypesetting for this context, convenient for chaining

Parameters:

braket_slot_typeset – BraKetSlotTypesetting

Returns:

ref to *this, for chaining

Public Static Functions

static inline Options make_default_options()
struct Defaults

Public Static Attributes

static constexpr auto vacuum = Vacuum::Physical
static constexpr auto metric = IndexSpaceMetric::Unit
static constexpr auto braket_symmetry = BraKetSymmetry::Conjugate
static constexpr auto spbasis = SPBasis::Spinor
static constexpr auto first_dummy_index_ordinal = 100
static constexpr auto braket_typesetting = BraKetTypesetting::ContraSub
static constexpr auto braket_slot_typesetting = BraKetSlotTypesetting::TensorPackage
struct Options

helper for the named-parameter constructor of Context

see the Context documentation for detailed description

Public Members

std::shared_ptr<IndexSpaceRegistry> index_space_registry_shared_ptr = nullptr

a shared_ptr to an IndexSpaceRegistry object

std::optional<IndexSpaceRegistry> index_space_registry = std::nullopt

an IndexSpaceRegistry object; used if index_space_registry_shared_ptr is null and it is nonnull

Vacuum vacuum = Defaults::vacuum

the Vacuum object

IndexSpaceMetric metric = Defaults::metric

the IndexSpaceMetric object

BraKetSymmetry braket_symmetry = Defaults::braket_symmetry

the BraKetSymmetry object

SPBasis spbasis = Defaults::spbasis

the SPBasis object

std::size_t first_dummy_index_ordinal = Defaults::first_dummy_index_ordinal

the first dummy index ordinal

std::optional<CanonicalizeOptions> canonicalization_options = std::nullopt

the default canonicalization options

BraKetTypesetting braket_typesetting = Defaults::braket_typesetting

the BraKetTypesetting object

BraKetSlotTypesetting braket_slot_typesetting = Defaults::braket_slot_typesetting

the BraKetSlotTypesetting object